Stalling Issue (Slant Six w/Holley 1920 Carburetor)

Duggie said

I've seen references to advancing ignition timing, but this is the first time I've read why. Why does crappy gas = advanced timing? Is there an indicator for too much advance besides ping?

I thought too that someone that knows more than me (okay anyone) would have mentioned the exhaust heat flapper by now. No? :poke:

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I don't see the exhaust hot air valve causing a hesitation. There can be other indicators for timing too high such as running rough. It can cause a rough idle if it gets too high. I tried my 170 around 20 and it idled too rough. I never drove it so I don't know if spark knock was present, but I didn't like how it idled at 20 so I backed it down to 12 and it idles great and is zippy as can be.